Pixel structure with reduced vacuum requirements

Abstract

A pixel structure, which may be used for infrared bolometers or other microelectromechanical systems (MEMS) devices, configured to increase immunity of the pixel to molecular heat transfer and reduce the vacuum requirements for a wafer level packaged device incorporating the pixel or an array thereof. In one example, the pixel has a perforated body or discontinuous surface structure.

What is claimed is: 
     
         1 . A sealed wafer level packaged infrared imaging sensor comprising:
 a vacuum packaged enclosure; and   at least one infrared bolometer disposed within the vacuum packaged enclosure, the infrared bolometer configured to receive infrared electromagnetic radiation in a wavelength range of interest, and including a body having a plurality of holes extending therethrough, a size of each of the holes being less than a smallest wavelength in the wavelength range of interest.   
     
     
         2 . The sealed wafer level packaged infrared imaging sensor of  claim 1 , further comprising:
 a substrate; and   a cap wafer disposed over and attached to the substrate, the cap wafer and the substrate together providing the vacuum enclosure.   
     
     
         3 . The sealed wafer level packaged infrared imaging sensor of  claim 2 , wherein the at least one infrared bolometer includes a plurality of infrared bolometers arranged in a two-dimensional array on the substrate and within the vacuum enclosure. 
     
     
         4 . The sealed wafer level packaged infrared imaging sensor of  claim 2 , wherein the at least one infrared bolometer further includes at least one support attached to the body and coupled to the substrate and configured to support the body above the substrate. 
     
     
         5 . The sealed wafer level packaged infrared imaging sensor of  claim 4 , wherein the substrate includes read-out circuitry. 
     
     
         6 . The sealed wafer level packaged infrared imaging sensor of  claim 5 , wherein the at least one support includes a metal and provides an electrical connection between the body and the read-out circuitry. 
     
     
         7 . The sealed wafer level packaged infrared imaging sensor of  claim 1 , wherein the wavelength range of interest includes a wavelength range from approximately 5 micrometers to approximately 14 micrometers. 
     
     
         8 . The sealed wafer level packaged infrared imaging sensor of  claim 7 , wherein the size of each of the holes is less than or equal to approximately 1 micrometer. 
     
     
         9 . The sealed wafer level packaged infrared imaging sensor of  claim 1 , wherein the body includes a layer of vanadium oxide. 
     
     
         10 . A sealed wafer level packaged device comprising:
 a vacuum packaged enclosure; and   a MEMs device disposed within the vacuum packaged enclosure, the MEMs device having a discontinuous surface structure configured to limit molecular heat transfer between the MEMs device and the vacuum packaged enclosure.   
     
     
         11 . The sealed wafer level packaged device of  claim 10 , wherein the MEMs device is a bolometer. 
     
     
         12 . The sealed wafer level packaged device of  claim 11 , wherein bolometer has a body having a plurality of holes extending therethrough to provide the discontinuous surface structure. 
     
     
         13 . The sealed wafer level packaged device of  claim 12 , wherein the bolometer is configured to receive infrared electromagnetic radiation in a wavelength range of interest, and a size of each of the holes being less than a smallest wavelength in the wavelength range of interest. 
     
     
         14 . The sealed wafer level packaged device of  claim 13 , wherein the wavelength range of interest includes a wavelength range from approximately 5 micrometers to approximately 14 micrometers. 
     
     
         15 . The sealed wafer level packaged device of  claim 14 , wherein the size of each of the holes is less than or equal to approximately 1 micrometer.